enzymes Flashcards
what is a saturation curve
the saturation curve in the rate vs conc of substrate graph, shows that at a certain high level of concentration of substrate, the rate of the reaction or velocity does not change.
what are the assumptions of of the michaelis and menten equation
- the equation relates to the initial rates of production of a product. so the backward reaction of the product is negligible.
- the enzyme conc. is less than the substrate conc.
- only one substrate is measured.
what is the steady state assumption
this assumption implies that the enzyme-substrate complex is in equilibrium with the concentration of enzyme.
what is the name of the plot formed by the 1/v vs 1/s. and what shape of does it give you
Lineweaver-Burk plot. It gives a straight line.
what does km mean and what does it signify
Km means the substrate conc. at half of Vmax. It signifies the affinity of the enzyme to the substrate, so lower the Km, higher the affinity.
what does Kcat mean
Kcat is the Vmax for any amount of enzyme
what does the specificity constant tell us
it tells us how efficient an enzyme is for a particular substrate.
what does turnover number mean
a number of substrates covered to product per second or catalytic site.
what are the types of enzyme inhibition
it can be reversible or irreversible
what are the types of reversible enzyme inhibition
- competitive
- uncompetitive
- non-competitive
what is non-competitive inhibition
the inhibitor binds at an allosteric site separate from the active substrate binding site. Thus in noncompetitive inhibition, the inhibitor can bind its target enzyme regardless of the presence of a bound substrate
what is an inhibitor constant
it refers to how potent a inhibitor is,smaller the Ki valu, greater the efficiency of the competitive inhibitor
what is AN EXAMPLE OF A CANER DRUG
methotextrate
function of methotextrate
inhibits synthesis of purines and pyramidnes by competitively binding to dihydrofolate reductase.
It is an anticancer drug
which amino acid is in the active site of the HIV protease
it is a dimer with asp in its active site
what are the inhibitors for hiv proteases
antiviral, eg: saquinavir
what is difp
it is a neurotoxin that irreversibly binds to serine proteases and acetylcholinesterase which prevents the cleavage of neurotransmitters in the post synaption junction.
types of irreversible inhibitors
- difp - nerotoxin
- sarin- neurotoxin
- aspirin
- penicillin
function of penicillin
irreversibly binds to the transpeptidase enzyme required for linking the peptidoglycan cell wall.
